Would it upset you if you had to mention something about our northern neighbors in Mexico? Well, never fear, it isn't likely to happen soon, and considering how conservative people are, we'd probably still consider Mexico to the south of us even if the compass read north. During all of human civilization, the north and south magnetic poles have always wandered about in the same general direction as today's. That hasn't always been the case, though. Through geologic time, the magnetic north and south poles, though not the geographic poles, have flipped back and forth. The last flip was only about 780,000 years ago.
So why bring this up now? Because the strength of the magnetic field
has been weakening rapidly in the last 150 years or so, and this might well be prelude
to a new reversal. Since the presence of the magnetic field protects us from many
harmful effects of the sun, a time of transition may be stressful. Luckily, we should
have hundreds to thousands of years to prepare should this not be a false alarm.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.